.back-to-top-button {
  display: flex;
  justify-content: center;
  align-items: center;
  cursor: pointer;
  font-weight: bold;
  background: white;
  width: 4rem;
  height: 4rem;
  position: fixed;
  right: 2rem;
  bottom: 2rem;
  border-radius: 50%;
  user-select: none;
  box-shadow: 0 0.4rem 0.8rem -0.1rem rgba(0, 32, 128, 0.15);
  transition: all 0.2s ease-out;
  visibility: hidden;
  opacity: 0;
  z-index: 1;
  border: 1px solid rgba(0, 32, 128, 0.1);
  outline: 0;
  color: inherit;

  &:hover,
  &:focus {
    transform: scale(1.1);
    box-shadow: 0 0.8rem 1.6rem -0.2rem rgba(0, 32, 128, 0.15);
    color: #35a8ff;
  }

  &:focus {
    box-shadow: 0 0.8rem 1.6rem -0.2rem rgba(0, 32, 128, 0.15), 0 0 2px 2px #35a8ff;
    outline-style: none;
  }

  &.is-visible {
    visibility: visible;
    opacity: 1;
  }

  .feather {
    width: 2rem;
    height: 2rem;
  }
}
